This invention relates to tinted contact lenses and methods of making tinted contact lenses.
Tinted contact lenses are often used for cosmetic purposes to change the apparent color of the wearer""s irises. For example, a person with brown or blue eyes but desiring to have green eyes may wear contact lenses having a greenish pattern thereon to mask the wearer""s irises with the greenish pattern.
Conventionally, tinting of contact lenses is achieved by printing a colored pattern onto a lens substrate via a pad printing process. It is to be understood that the term xe2x80x9ctintedxe2x80x9d is intended to encompass colored, patterns of translucent and/or opaque pigmentations. The pad printing process employs a generally flat steel plate also known as a clichxc3xa9. A pattern (or depression) is etched into the clichxc3xa9 by a photo-etching process. In operation, ink placed in the pattern is transferred to the lens substrate by a printing pad. To achieve a tinted lens of multiple colors, different colored inks are placed into three or fewer different patterns and serially transferred to the lens substrate by printing pads.
A disadvantage associated with conventional methods of tinting contact lens substrates is that such methods cannot achieve patterns of high resolution. In other words, the printed pattern on the lens substrate does not have nearly the detail of a human iris. The inability to achieve patterns of high resolution also prevents use of more than three different patterns on a lens substrate. As such, an observer viewing the wearer""s eyes from five feet away or closer may determine that the wearer is wearing tinted lenses. Another disadvantage is the extensive labor needed to etch a pattern into the clichxc3xa9. Typically, four to six xe2x80x9cman-hoursxe2x80x9d are required to etch each pattern. Moreover, the pattern must generally be etched to precise depths so that the ink can be transferred effectively. Etching to such precisea depths is often difficult. In many intricate or detailed patterns, depth variances of 3-5 microns may render the clichxc3xa9 useless. Another disadvantage is that the corrosive chemicals (e.g., ferric chloride and hydrochloric acid) used to etch the pattern in the clich6 are hazardous both to workers and to the environment. Thus, enhanced care and cost are needed in using and disposing of the chemicals.
Among the several objects and advantages of the present invention may be noted the provision of an improved method for tinting contact lens substrates; the provision of such a method of tinting a lens substrate in which the tinted lens substrate more closely resembles a human iris than does a tinted lens substrate made by conventional methods; the provision of a method of tinting a lens substrate to form a tinted lens having a pattern of greater intricacy; the provision of an improved method of forming a pattern in a clichxc3xa9; the provision of a method of forming a precise, intricate pattern in a clichxc3xa9; the provision of such a method of forming such a pattern in a less labor-intensive manner; the provision of a method of forming a pattern in a clichxc3xa9 without use of hazardous chemicals; and the provision of a tinted contact lens having a lens substrate a colorant image printed thereon of greater resolution than images printed on prior art tinted contact lenses.
In general, a method of the present invention for making a tinted contact lens for insertion into an eye comprises providing a plate having a surface, and lasing the plate to form at least one depression in the surface of the plate. The depression is of a shape constituting an iris portion pattern. A fluent colorant is introduced into the depression. The colorant is then transferred from the depression to a lens substrate in a manner so that the colorant colors the lens substrate in a colorant pattern of substantially the same shape as the iris portion pattern of the depression.
In another aspect of the present invention, a method of making a tinted contact lens for insertion into an eye comprises digitizing an image of a human iris nto a computer. The digitized image is separated into a plurality of digitized image portions, which are used to form a plurality of depressions in a plurality of clichxc3xa9 portions. Each depression is of a shape constituting an iris portion pattern. Fluent colorants are introduced into the plurality of depressions. The colorants are transferred from the depressions to the lens substrate in a manner so that the colorants color the lens substrate in a plurality of colorant patterns of substantially the same shape as the iris portion patterns of the depressions. The colorant patterns combine with one another to color the lens substrate in a manner to simulate a human iris.
In yet another aspect of the present invention, a tinted contact lens for insertion into an eye comprises a contact lens substrate and an iris-simulating pattern on the lens substrate. The iris simulating pattern comprises at least four distinctly colored colorants.
Other objects and features will be in part apparent and in part pointed out hereinafter.